Optical and fluorescence spectroscopy of Eu2O3-doped P2O5–K2O–KF–MO–Al2O3 (M = Mg, Sr and Ba) glasses

Fluorophosphate glasses of composition, P2O5 + K2O + KF + MO + Al2O3 + xEu2O3 (M = Mg, Sr and Ba; x = 0.01, 0.05, 0.1, 1.0, 2.0, 4.0 and 6.0 mol%) were prepared and characterized their optical properties. Crystal-field (CF) analysis revealed a relatively weak CF strength around Eu3+ ions in the Ba based fluorophosphate glasses. The Judd-Ofelt parameters have been estimated from the oscillator strengths of 7F0 → 5D2, 7F0 → 5D4 and 7F0 → 5L6 absorption transitions of Eu3+ ions and were used to evaluate the radiative properties of the 5D0 → 7FJ (J = 0–4) transitions. Considerable variation has been observed in the relative intensity ratio of 5D0 → 7F2 to 5D0 → 7F1 transitions of Eu3+ ions due to change in the alkaline earth metal ions. The decay of the 5D0 level shows single exponential and less sensitive to Eu3+ ions concentration as well as MgO/SrO/BaO modifiers.

Research Highlights
► Optical properties of Eu3+:P2O5-K2O-KF-MO-Al2O3 (M = Mg,Sr and Ba) have been studied.
► Stark levels of the Eu3+ ion emission suggest a local C2v symmetry.
► Relatively weak crystal-field strength found around Eu3+ ions in Ba modified glass.
► The decay rate of the 5D0 level exhibits single exponential nature in studied glasses.
► The quantum efficiency for the 5D0 level is found to be 95%.